Many tractor-mounted implements include hydraulic consumers such as motors and cylinders. Each hydraulic consumer is hydraulically coupled to a respective control valve on the tractor. Typically a tractor may include six or eight directional control valves (or spool valves) each having an associated coupling member and a user interface device. The couplings are mounted at various locations on the tractor, the majority being positioned at the rear of the vehicle for receiving associated pipework from attached implements. The user interface device typically comprises a joystick, lever or switch which is operable by a driver.
In operation a driver controls the various consumers by operation of a user interface device which directly or indirectly controls the associated directional control valve so as to control the delivery of pressurised fluid to the hydraulic consumer.
Over the past two decades or so the trend for agricultural implements has been for an increase in hydraulic consumers to remotely control various functions previously controlled manually. For example, a modern trailer typically includes hydraulics cylinders to control the opening of the rear tailgate, the steering axle and lifting of the body.
Modern tractors, and particularly high horse power tractors, include a driver terminal which includes a display and associated user input means such as buttons located around the display. The terminal serves primarily to communicate the state of various functions on the tractor and implement during operation. It is known to display a graphical representation of the various hydraulic consumers coupled to the tractor to communicate the current status of each consumer to the driver. Such functionality is available for example on the Datatronic III system fitted to selected Massey Ferguson tractors.
The increase in number of hydraulic consumers makes operation of the implement more and more complex for the driver. The complexity and demands on the driver's memory is compounded by the regular interchanging of implements which come with different functionality.